The present invention involves isolating or separating paclitaxel or other taxanes from materials containing one or more taxanes using an amino containing material supported by a solid matrix such as PBS resins. The present invention also involves purifying a biomass extract comprising taxanes.
It is well known that various taxanes, e.g., paclitaxel, can be purified by using chromatographic techniques. Chromatographic media such as silica, alumina, alkyl-bonded silica resins such as C18 and C8, and polystyrene divinylbenzene resins have been reported in the literature to be useful for this purpose. However, depending on the nature of the purification process, all of these media have limitations.
It has been discovered that amino containing material attached to a matrix (e.g., PBS resins) may provide superior selectivity and resolution over other conventional chromatographic resins used to isolate and purify taxanes. Therefore, amino containing materials attached to a matrix (e.g., PBS resins) can be utilized to perform separations more efficiently than other resins in the area of taxane purification. For instance, in the literature, the separation of paclitaxel (taxol A) and cephalomannine (taxol B) has been described as difficult. The separation of these compounds is greatly facilitated using one or more PBS resins, as described herein. Also, since PBS resins can be utilized using organic solvents, the resin may be more easily loaded and samples can be applied at higher loading than reverse-phase resins such as C18, C8, and polystyrene divinylbenzene.
PBS resins are primarily used in ion-exchange chromatography applications. Very few taxanes contain an ionizable group such as carboxyclic acid or amine groups and therefore the mode of interaction is not traditional ionic exchange. Unexpectedly, the use of PBS resins provides superior selectivity and resolution in isolating or purifying taxanes. In the present invention, the PBS resins work best when small amounts of an acidic modifier or salt are used in the mobile phase.
In addition, we have discovered that the amino groups of the PEI polymer can be functionalized by alkylation, arylation, or acylation. We have also discovered that PBS resins may be used to perform preparative and analytical separations of taxane compounds. Preparative separations can be carried out in a batch, semi-continuous, or continuous mode. Semi-continuous mode may be in the form of simulated moving bed (SMB) chromatography.